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Three wires, of the same diameter, are connected in turn between two points maintained at a constant potential difference. Their resistivities and lengths are rho and L (wire A), 1.2rho and 1.2L (wire B), and 0.9rho and L (wire C).
1. Rank the wires according to the rate at which energy is transferred to thermal energy within them, greatest first. (Use only ">" or "=" symbols. Do not include any parentheses around the letters or symbols.)

Respuesta :

Answer:C > A > B

Explanation:

Given

Three wires A , B and C with Resistivities and lengths as given

A [tex]\rho[/tex]  and L

B [tex]1.2\rho[/tex] and  1.2 L

C [tex]0.9\rho[/tex]  and  L

we know that resistance is given by

[tex]R=\frac{\rho L}{A}[/tex]

where A=cross-section of wire

It is given that common Potential is applied for three wires

Resistance of A , B and  C are

[tex]R_a=\frac{\rho L}{A}=R_o[/tex]

[tex]R_b=\frac{1.2\rho \times 1.2 L}{A}=1.44R_o[/tex]

[tex]R_c=\frac{0.9\rho L}{A}=0.9R_o[/tex]

Thermal Energy is given by

[tex]E=\frac{V^2}{R}[/tex]

for same Potential difference

[tex]E_a=\frac{V^2}{R_o}[/tex]

[tex]E_b=\frac{V^2}{1.44R_0}[/tex]

[tex]E_c=\frac{V^2}{0.9R_0}[/tex]

Thus maximum heat is generated in wire C and minimum in wire B

thus C > A > B

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